Saute the onions in 1 oz. of the clarified butter over medium heat. Add the balsamic vinegar and reduce heat to low. Cook until balsamic is reduced and onions are reduced down.

To assemble sandwich: Place cheese on both slices of the bread. Place 1/4 of onions on top of cheese along with 2 oz. of sliced bresaola. Brush outside of sandwich with clarified butter. Saute in nonstick pan on both sides until bread takes on golden color. Place in 375 degree oven to melt cheese if it has not melted.